Malice by Chris Wooding
Once you get into the story, there's no way out. Everyone's heard the rumors. If you gather the right things and say the right words, you'll be taken to Malice, a world that exists inside a horrifying comic book. It's a world that few kids know about ... and even fewer survive. Seth and Kady think it's all a silly myth. But then their friend, Luke, disappears and suddenly the rumors don't seem silly after all. Malice is real. Malice is deadly. And Seth and Kady are about to be trapped inside.